Magnetic type head actuating arrangement



Oct. 15, 1968 w. STUIBER ET 3,405,793

MAGNETIC TYPE HEAD ACTUATING ARRANGEMENT Original Filed March 21, 1966 2 Sheets-Sheet l mvsmom;

Oct. 15, 1968 w. STUIBER' ET 3,405,793

MAGNETIC TYPE HEAD ACTUATING ARRANGEMENT Original Filed March 21, 1966 2 Sheets-Sheet 2 BY A a Mamet \w mi- ATTORNEY United States Patent 3,405,793 MAGNETIC TYPE HEAD ACTUATING ARRANGEMENT Walter Stuiber, Nurnberg, and Georg Mueller, Schwalbach, Germany, assignors to Max Grundig, Furth, Bavaria, Germany Original application Mar. 21, 1966, Ser. No. 535,989, now Patent No. 3,349,885, dated Oct. 31, 1967. Divided and this application Aug. 9, 1967, Ser. No. 659,477 Claims priority, application Germany, Mar. 20, 1965, G 43,130 5 Claims. (Cl. 197-16) ABSTRACT OF THE DISCLOSURE The shaft of a rotary type head carries an armature Which is attracted by an electromagnet when a selected type face of the type head is located opposite an impression area so that the force of the electromagnet presses the type face against the impression area. The armature has dilferent armature portions influencing the actuating pressure in accordance with the area of the respective type face.

Background of the invention The present application is a divisional application of our copending application Ser. No. 535,989, now issued as US. Patent 3,349,885.

It is known to move the type bars of a manual typewriter to a position of readiness located in the proximity of the platen, and to then produce an imprint by energizing an electromagnet which presses the type bar against the platen.

Rotary type heads having type faces arranged 111 oncurnferential rows and axial columns are known which are turned and axially shifted until a selected type face is located opposite the impression area. Whereupon the type head is mechanically tilted to make an impression.

The first construction is incapable of operating at high speed, and the second construction produces undesirable noise.

Summary of the invention It is one object of the invention to provide an improved type head actuating arrangement in which the printing pressure of the type head is produced by an electromagnet.

Another object of the invention is to provide a type head with an armature moving therewith and having different armature portions respectively corresponding to type faces having different impression areas so that the fiux of the electromagnet attracting the armature is different for different type faces and the printing pressure is varied in accordance with the impression area of the respective selected type face.

With these objects in view, the present invention provides a rotary type head which is moved by an electromagnetic means to an impression making position when a selected type face of a type head is located opposite an impression area, and electromagnetic means which are energized under the control of a switch actuated when the type head is in a position of readiness in which the selected type face is located opposite the impression area.

It is known that type faces having different areas, for example the type face representing a period, and a type face representing a M, produce imprints of different density, darkness and appearance if pressed with the same force against the impression area.

In accordance with the present invention, an armature member having armature portions respectively associated with the type faces of the type head, rotates and moves ice with the same so that the respective armature portion is located opposite electromagnetic means when the corresponding type face is located opposite the impression area. The size of each armature portion is selected in accordance with the size of the respective type face so that the force at which any selected type face is pressed against the impression area, varies in accordance with the size and area of the character on the respective type face.

An embodiment of the invention comprises a rotary type head having type faces arranged in circumferential rows and axially extending columns, and being mounted movable between a plurality of positions of readiness in which different type faces are located opposite an impression area; selector means including keys, associated with different type faces; drive means controlled by the selector means to move the type head to a position of readiness in which a selected type face is located opposite the impression area; electromagnetic means located in the region of the impression area; and an armature drum connected with the type head for movement therewith.

The armature drum has a plurality of armature portions respectively corresponding to type faces and being respectively located opposite the electromagnetic means when the corresponding type face of the type head is located opposite the impression area. In this moment, the electromagnetic means is energized and attracts the respective armature portion with a magnetic force depending on the size of the armature portion for moving the type head to a position in which the selected type face engages the impression area.

In the preferred embodiment of the invention, the armature drum is connected with the type head for rotation and axial movement and has a plurality of circumferentially spaced armature portions respectively corresponding to columns of the type faces on the type head. The type faces in the same column have substantially the same area, and type faces located in different columns have different areas. The armature portions extend in column direction and are constructed as different magnetic resistances corresponding to the areas of the type faces of the respective associated columns so that large type faces in some of said columns are pressed against the impression area with a greater magnetic force than small type faces located in other columns.

Since the armature drum is connected with a type head for axial movement, the armature portions are elongated in axial direction so that different axial sections of each armature portion are attracted by the same magnetic force when type faces of the same column are located opposite the impression area.

In the preferred embodiment of the invention, the drive means of the type head and armature drum include a drive shift, a one revolution clutch, an eccentric cam connected with the one revolution clutch, and rotated in the engaged position of the same, and a cam follower operated by the cam. A switch is connected in the circuit of the electromagnetic means and actuated by the cam follower to energize the electromagnetic means at the proper moment in which the selected type face is located opposite the impression area.

In order to cause only a very short energization of the electromagnetic means the switch is connected into a circuit including resistors and a capacitor so that capacitor is charged over the resistances and is discharged over the closed switch to provide a short energizing impulse for the electromagnetic means.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Brief description of the drawing Description the preferred embodiments Office printing machines are known whose general construction is similar to a typewriter, butwhich use a rotary type head provided Lwith a plurality of peripheral circular rows of type faces arranged in columns. The type head rotates until it is stopped under the control of a key board in a position in which a selected column is located opposite the impression area, and tilted or'axially shifted until a selected type 'face in the respective column is located opposite the impression area. Thereupon, the type head is moved toward the impression area to produce an imprint of the selected type face.

An office printing machine of this type is disclosed, for example, in the US. Patent 2,879,'S76.The embodiments of the invention illustrated in FIGS. 1 to 4 are applied to printing machines having a rotary type head. In the embodiment of FIG. l, the type head 26 is barrel-shaped and has type faces arranged in circular rows 26a, and in columns 2612. A column 26b is' selected by stopping the rotary type head in the respective angular position, and 'a character of the column is selected by tilting the type head between the terminal positions shown in solid and broken lines, respectively.

In the embodiment of FIG. 4, the; type head 26 is cylindrical, a column of type faces 261 is selected by stopping rotation of the type head, and a particular type face in the selected column is selected by raising the type head 26' to such a height that the respective circular row of type faces 26a is located opposite the impression area of platen 26. These constructions are known, and not an object of the present invention.

Referring to the embodiment of FIG. 1, the typehead 26 is secured to a hollow shaft 27 which has at its lower end a flange 27a. Shaft 27 and type head 2:; are mounted for rotary and axial movement on a-support shaft which is tiltable toward and away from platen=20 for moving the type head between a selecting position spaced from the impression area, and an impression making position in which a selected type face engages'the impression area. An armature drum 28 is secured by hub 28a to the hollow shaft 27 and rotates in synchronism with the type head. Armature drum 28 rests on the top face 29a of a stop member 29 which is secured by a pin 30 to support shaft 25. Flange 27a is located in a cut-out 29b of stop member 29 so that axial movement of shaft 27 and type head 26 is limited.

Armature drum 28 has a plurality of axially extending ribs 280 separated by grooves 28b. The number of the projecting armature portions 280 is the same as the number of columns of type faces on the type head, and also the same as the number of type faces in each circular row 26a, and each armature portion 280 is located opposite the pole shoes of core 21b when a corresponding column of type faces 26b is located opposite platen 20.

As best seen in FIG. 2, the magnetizable armature portions 28c have different circumferential width so that the flux of electromagnetic means 21 encounters different resistance depending on Whether a smaller or larger magnetizable armature portion 28c is located opposite core 21b.

The circumferential extension of each armature portion 230 is selected in accordance with the size and area of the character on the type faces in the respective column of type faces 25b. Since the magnetic force is the same for all type faces in the same column, type faces having differentareas are placed in different columns, and type faces having substantially the same area are placed in the same column.

A spring, not shown, urges the type head assembly to the right as viewed in FIG. 1 against an abutment 31 and into the selecting position, and whenever electromagnetic means 21 is energized, armature 28 is attracted, and the assembly is tilted in counterclockwise direction so that the selected type face Whichis located opposite the impression area of platen 20 in a position of readiness, is moved to the impression making position and pressed against the platen with a force which depends, on the circumferential extension and magnetic reluctance of the respective armature portion 280 located opposite electromagnetic means 21. In the embodiment of FIG. 4', in which the type head is cylindrical, an armature 28, as described with reference to FIGS. 1 and 2, cooperates with electromagnetic means 21 to move type head 26 from the illustrated selecting position to the impression making position in which one of the type faces engages the impression area on platen 26. The type head 26 is raised or lowered,-insteadof being tilted as in the construction of FIG. 1 for the selection of a particular type face, but since the means for raising or tilting the type head are well known and not an object ofthe invention, reference is made to the US. Patent 2,879,876 which discloses key levers acting through interposers on selecting bails for placing the type head through selecting wires in a position of readiness. in which a selectedtype face is located opposite the impression-area. After the selection of the type face has been completed, a clutch is actuated which couples the drive means to the type head. to produce the imprint. v

A similar arrangement may be, used in the apparatus of the invention for carrying out the selection and the placement of a selected type face in a postion of readiness opposite the impression area. e

In accordance with the present invention no clutch connectingdrive means with printing means is provided, but as shown in FIG. 3, a Wire 51 is moved in the direction of the arrow 62 when a type face has been selected, and shifts a stop member 66 about its pivot 64 to turn in the direction of the arrow 65 so that a coupling member 68 which is pivotally mounted on a coupling disc 70 secured to a shaft 72 it released, and is turned by spring 71 in counterclockwise direction as viewed in FIG. 3 to a position in which its coupling projection 75 engages a corresponding recess in a toothed coupling wheel 74 which is secured to a drive shaft 73. The shaft 72 which is secured to coupling disk 70, carries an eccentric cam 76 which cooperates with a lever 77 mounted on a shaft 79 and being urged by spring 78 into engagement with eccentric cam 76. A switch 19 has an actuating button 80 cooperating with cam follower lever 77. I

Electromagnetic means 21 is connected in series with switch 19 and two resistors R1 and R2, and an adjustable resistor R3 as shown in FIG. 5.-A capacitor C is connected to the terminal 51 and to a point between resistors R1 and R2. A voltage source is applied to terminals 50 and 51. The capacitor is charged through resistor R1, and when switch 19 is closed, the capacitor discharges through resistors R2, R3 and the winding of electromagnetic means 21 so that the electromagnetic means 21 is energized for a short time. The amount of current flowing through the winding of electromagnetic means 21 can be varied by adjustment of resistor R3.

When stop member 66 releases coupling member 68, and one revolution coupling 60 is engaged, eccentric member 76 is turned and cam follower 77 actuates switch 19 so that winding 21a is energized, and armature 28, together with the type head assembly, is attracted toward electromagnetic means 21 for moving the type head 26 of the embodiment of FIG. I, or 26' of the embodiment of FIG. 4 to an impression making position in which the previously selected type face engages the impression area.

After the impression has been made, coupling disk 70 with coupling member 68 complete one revolution, and arm 67 of coupling member 68 is stopped by stop member 63 so that coupling projection 75 releases coupling pinion 74, and shaft 72 stops.

From the above description of embodiments it will become apparent that switch means 19, 80, 81 in the circuit of electromagnetic means 21 is actuated by actuating means 76, 77 under the control of drive means including the one revolution clutch 60 and drive shaft 73.

It will be understood that each of the elements de scribed above, or two or more together may alsofind a useful application in other types of type head actuating arrangements differing from the types described above.

While the invention has been illustrated and described as embodied in a rotary armature connected to a type head and cooperating with an electromagnetic for moving the type head toward a platen, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the followin claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. Type head actuating arrangement comprising, in combination, means having an impression area; a rotary type head having an axis and including type faces arranged in circumferential rows and axial columns located in radial planes passing through said axis, type faces located in the same column of said type head having substantially the same area, and type faces located in different columns having different areas, said type head being movable in one radial plane passing through said impression area between a selecting position spaced from said impression area and an impression making position engaging the same with a type face located in said one radial plane, said type head in said selecting position being movable between a plurality of positions of readiness in which different type faces are located opposite said impression area and in said one radial plane; power drive means for moving said type head in said selecting position to a position of readiness in which a selected type face is located opposite said impression area; electromagnetic means located in said one radial plane in the region of said impression area; an armature drum connected with said type head for rotation therewith and having a plurality of circumferentially spaced armature portions respectively axially aligned with said columns of type faces of said type head, said armature portions being respectively located opposite said electromagnetic means in said one radial plane when a type face of the respective column is located opposite said impression area in said one radial plane in said position of readiness, each of said armature portions having a magnetic reluctance cor responding to the areas of the type faces of the respective associated column located in the same radial plane so that type faces in different columns havin different areas are pressed against said impression area by a magnetic force proportionate to the size of the respective area whereby uniform imprints are produced by said type faces.

2. Type head actuating arrangement as claimed in claim 1 wherein said type head is connected with said armature drum for axial movement; and wherein said armature portions are elongated in axial direction and each armature portion has a uniform circumferential width along the length thereof so that different axial portions of each armature portion are attracted by the same mag netic force when type faces of the same column are located opposite said impression area.

3. A type head actuating arrangement comprising, in combination, means having an impression area; a rotary type head having type faces arranged in circumferential rows and axially extending columns, said type head being mounted movable between a plurality of positions of readiness in which different type faces are located opposite said impression area; selector means associated with different type faces; drive means controlled by said selector means to move said type head to a position of readiness in which a selected type face is located opposite said impression area, said drive means includin a drive shaft and a one revolution clutch; electromagnetic means; an armature drum connected with said type head for movement therewith and having a plurality of armature portions associated with different type faces and being respectively located opposite said electromagnetic means when the respective type face is located opposite said impression area in said position of readiness so that said electromagnetic means attracts the respective armature portion for moving said type head from said position of readiness to an impression making position in which the selected type face is pressed against said impression area; an eccentric cam connected with said one revolution clutch and rotated in the engaged position of the same, and a cam follower operated by said cam; and a circuit means comprising a switch connected with said electromagnetic means and actuated by said cam follower to energize said electromagnetic means.

4. A type head actuating arrangement as claimed in claim 3 wherein said circuit means includes a plurality of resistors, and a capacitor connected in parallel with said switch and said electromagnetic means so that said capacitor discharges and produces a short electric impulse for energizing said electromagnetic means.

5. A type head actuating arrangement as claimed in claim 4, wherein one of said resistors is connected in series with said electromagnetic means and in parallel with said capacitor, and is adjustable for varying the current of the electric impulses flowing through said electromagnetic means for adjusting the magnetic force of said electromagnetic means and thereby the impression force of said type faces.

References Cited UNITED STATES PATENTS 2,847,105 8/1958 Carroll 197l6 2,875,879 3/1959 Auerbach l97-l4 2,879,876 3/1959 Palmer et al 197-16 2,891,649 6/1959 Peterson 197-14 3,068,985 12/1962 Arthur 197-14 3,168,182 2/ 1965 Bernard et al 197-55 3,286,806 11/1966 Schoenfelder 19716 3,291,041 12/1966 Burchfield et al. 197-55 X ROBERT E. PULFREY, Primary Examiner.

EDGAR S. BURR, Assistant Examiner. 

